In ancient times — say, the '60s, '70s or maybe even the '80s — children were expected to waste a good deal of their time. They'd spend hours riding their bikes to nowhere, or drawing with chalk.

Their parents didn't worry that this meant they were going to end up drug addicts, or at least at a second-tier college. But that was before something began taking over all waking hours of the day.

School.

When we think about how different childhood is today — structured, supervised, stressful — we tend to blame helicopter parents or the culture of fear. But Peter Gray, author of the basic psychology textbook used in colleges across the country (including Harvard), says, "The part [of the problem] that we don't give enough weight to is the increasing amount of influence of schooling."

Think about how school dominates the lives of kids today. When Gray, now a white-haired professor, was growing up, the school year was five weeks shorter. I remember that, too. A three-month summer vacation — Bliss! No one was freaking out about the "summer slide" — kids forgetting the lessons they left behind in May. Summer was seen as the time kids needed to recharge, not a brain drain.

As for what happened during the school year itself, there was little or no homework in the lower grades. No nightly homework sheets, or reading log. (Forcing your kids to read a certain amount each day turns out to be the perfect way to make them hate reading. Try it!)

Gray, who was at Clemson University this week to give a talk at the U.S. Play Coalition, as was I, says that parents are expected to continue the school day at home, reviewing and signing their kids' homework. They're also expected to volunteer at the school, and visit it for a million reasons. It's as if, for the whole family, school has become the biggest force in their lives. Parents are told that this is how it has to be if they want their kids to succeed.

Once parents are taught to be "school partners," says Gray, "all of society develops the view that children grow best when carefully monitored and guided. And it used to be children grow themselves."

This is not to say that kids learn algebra by climbing trees. But they do learn how to gauge risk and handle fear. By playing a game of catch, even against a wall, they learn how to do something over and over to get it right. By playing with friends, they learn how to control their impulses, share, go a little easier on the youngest kid (that's empathy) — all the arts of being human.

These activities don't stunt intellectual development, they make young minds curious and creative.

In an essay titled, "Be Glad of Our Failure to Catch Up with China in Education," Gray compares our education system to China's, where grammar school kids spend nearly 10 hours a day studying. High schoolers face a 12.5-hour school day.

Kids are forced to endure this "for one and only one reason, to get a high score on the gaokao, the national examination that is the sole criterion for admitting students to college," writes Gray.

What happens to those high-scoring winners? "A common term used in China now to refer to the general results of their educational system is gaofen dineng, which means, literally, high scores, but low ability. Because students spend nearly all of their time studying, they have little chance to do anything else," like develop interests, physical stamina or social skills.

That's a "success" America would do well to avoid.

To raise the kind of engaged and eager kids who grow into entrepreneurs and happy citizens, we need to stop school from seeping into every hour and activity of the day. Fooling around turns out to be the best schooling around.